1. Field of the Invention
The present invention relates to a method for producing flexible electroactive polymer generators.
2. Description of the Related Art
Electroactive polymers (EAP) are polymers which change their shape when an electric voltage is applied. As a result, electroactive polymers are usable as actuators. However, electroactive polymers also allow an operation in the manner of a generator, in which a mechanically induced expansion of the electroactive polymer is directly converted into electrical energy. Such energy converters are referred to as EAP generators. The conversion of the expansion of the electroactive polymer into electrical energy takes place on a capacitive basis by the shifting of charges. During the conversion of mechanical energy into electrical energy with the aid of electroactive polymers, the EAP generator, including at least one component which has two resilient electrodes between which a tier made of electroactive polymer is situated, is strained as a result of the action of an external force. In the state of maximal strain of the EAP generator, the electroactive polymer is acted upon by electrical charges below the breakdown field strength. When the action of the external force is reduced, the electroactive polymer relaxes due to its elasticity. During this phase, the energy stored in the EAP generator increases. This process constitutes the actual conversion of the mechanical into the electrical energy. As soon as the EAP generator is completely relaxed, the electroactive polymer which is acted upon by an electrical charge is discharged, whereby the EAP generator rewinds to its original length. The energy generation cycle may start again.
EAP generators may have multiple layers, each including two electrodes between which a tier made of electroactive polymer is situated, the layers being combined to form one stack or multiple stacks. These stacks are referred to as EAP stacks. For the present invention, however, the term ‘EAP stack’ is also understood to mean specific embodiments which have only one layer made of two electrodes having an interposed tier made of electroactive polymer. EAP stacks within the sense of the present invention are thus stacks which have at least one layer, including two preferably flexible electrodes and a tier made of electroactive polymer situated between the two electrodes.
Various methods for manufacturing EAP stacks are known from the related art. According to one method, individual layers, including two electrodes between which a tier made of electroactive polymer is situated, are placed on top of each other and then wired together from the outside.
An EAP generator and a method for manufacturing EAP stacks are known from published German patent application document DE 10 2009 054 035 A1, for example.
The EAP stacks manufactured with the known methods are usable as actuators or as generators. However, these EAP stacks are only effective with a deformation in the direction of their longitudinal axis, but not during deflection.